target/mips: Remove tswap() calls in semihosting uhi_fstat_cb()

target/mips: Remove tswap() calls in semihosting uhi_fstat_cb()

In preparation of heterogeneous emulation where cores with
different endianness can run concurrently, we need to remove
the tswap() calls -- which use a fixed per-binary endianness.

Get the endianness of the UHI CPU accessed using
mips_env_is_bigendian() and replace the tswap() calls
by bswap() ones when necessary.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20241211230357.97036-3-philmd@linaro.org>